摘要
通过宏观分析、金相和断口微观分析、理化性能试验,对某型88.9mm(3英寸)压裂弯头爆裂原因进行了分析。结果表明:该弯头发生爆裂的原因是由于弯头外弧侧受携砂液的冲刷腐蚀作用,外弧侧内壁组织由硬度较高的马氏体变为硬度较低的回火索氏体,抗冲刷能力明显减弱,壁厚减薄严重,造成结构不均匀,应力高度集中,在氯离子等腐蚀元素作用下,产生点蚀坑,在点蚀坑底部产生应力腐蚀裂纹,裂纹扩展,导致弯头开裂失效。建议减少施工次数,增加弯头检测频次。
Failure causes of 3in fracturing elbow were investigated through visual morphology analysis,physicochemical properties test,and fracture microscopic analysis.Results show that the elbow is under the erosion of fracturing fluid carrying sand and the wall changed from marten site with high hardness to lower hardness of tempered cable.Anti scouring ability decreased ssignificantly and the wall thickness was reduced.The structure was not uniform and the stress concentration was high.Under the action of chloride ion and other corrosive elements,the inner wall of outer arc side pitted pit,and stress corrosion cracking appeared at the bottom of the pit.Crack propagation leaded to the failure of elbow cracking.Half the number of construction and double frequency detection were recommended.
出处
《石油矿场机械》
2016年第6期54-60,共7页
Oil Field Equipment
关键词
弯头
冲刷
腐蚀
elbow
scouring
corrosion